Arrangement for extinguishing of a disconnecting switch arc



1955 H FORWALD 2,758,179

ARRANGEMENT FOR EXTINGUISHING OF A DISCONNECTING SWITCH ARC Filed Sept. 15, 1953 /n yen for. v HHHKON FORM/m0 United States Patent ARRANGEMENT FOR EXTINGUISHING OF A DISCONNECTING SWITCH ARC Haakon Forwald, Ludvika, Sweden, assignor to Allmanna Svenska Elektnska Aktiebolaget, Vasteras, Sweden, a corporation of Sweden Application September 15, 1953, Serial No. 380,215 Claims priority, application Sweden September 26, 1952 3 Claims. (Cl. 200148) In compressed air circuit breakers with a disconnecting switch which is so arranged that it interrupts a resistance in parallel with the main breaking gap, it is known to expose the are appearing at the breaking to a flow of air in order to achieve an extinguishing of the are.

For this purpose it has been proposed to connect the pipe-formed disconnecting switch arm with a compressed air pipe line and to arrange a mouthpiece close to the contact point of the disconnecting switch arm so that the arc appearing at the interruption is exposed to a flow of air. The arc has, however, as known a tendency to avoid such a flow of air directed against it and it has therefore been necessary to broaden the escaping air flow so that the arc cannot avoid it. The air escaping from such an outlet will, however, be spread with an angle of 20 and it has therefore been necessary to arrange the outlet opening in a comparatively large distance from the arc in order that the air shall get such a width that it strikes the arc. On the other hand a minimum air spread is necessary to get an efiective extinguishing of the arc and it has therefore been necessary to make the outlet opening comparatively large with a large air consumption.

The present invention concerns an arrangement through which an efiective blow out of the are within a sufficiently broad space is possible with a considerably smaller air consumption than in the hitherto proposed arrangement. According to the invention the hollow disconnecting switch arm is connected with a source for compressed air, but in a suitable distance from the contact point of the disconnecting switch, the disconnecting switch arm is provided with a row of outlet openings for compressed air perpendicularly to the disconnecting switch arm so that a plurality of air flows stream out against the are, said outlet openings being arranged at so large a distance from the are that the said air flows near the are are joined to form a single comparatively broad but thin flow of air having a large velocity. Instead of making the disconnecting switch arm hollow it is also possible to attach a pipe line on the side of it.

The advantage of the above arrangement is to be seen in the circumstance that the outlet openings can be arranged close to the breaking point and also in that the air consumption is lower.

Patented Aug. 7, 1956 On the accompanying drawing a form according to the invention is shown. Fig. 1 shows the disconnecting switch seen from the side at the breaking moment and Fig. 2 from above. 1 designates the pipe formed disconnecting switch arm, which in one end is flattened to form a knife 2. To the disconnecting switch arm is attached an air distributor 4 which by the opening 3 is in communication with the switch arm. 5 designates outlet openings of mouthpieces on the air distributor. 6 designates the stationary disconnecting switch contact which is arranged on the insulator designated by 7. When opening, air is admitted to the pipe formed arm at A, which air streams to the distributor 4 and out through the mouthpieces 5 where it forms the cone shaped flows C which overlap each other at D and thus act to extinguish the arc B.

I claim as my invention:

1. An arrangement for extinguishing the arc in a disconnecting switch, comprising a disconnecting switch arm, an air distributor arranged perpendicularly to and supplied with air from the said switch arm, and a number of air outlet mouthpieces spaced from each other along said distributor, the distance between adjacent mouthpieces being such that the air flows from the mouthpieces overlap each other to form at the are a comparatively thin and broad continuous flow of air.

2. A disconnecting switch comprising a stationary contact, a disconnecting switch arm carrying a movable contact and having a passage for the supply of compressed air, a compressed air distributor movable with the said arm and supplied with compressed air from said passage, and a plurality of air openings arranged in a substantially straight line for the delivery of air from said distributor in conical streams that merge with each other to form a relatively shallow and broad air curtain of high velocity that intersects the are formed between said contacts when the switch is opened.

3. An arrangement for extinguishing the arc in a disconnecting switch, comprising a hollow disconnecting switch arm, an air distributor arranged perpendicularly to the said switch arm and having compressed air delivered thereto through the said hollow arm, and a number of air outlet mouthpieces spaced from each other along said distributor, the distance between adjacent mouthpieces being such that the air flows from the mouthpieces overlap each other to form at the are a comparatively thin and broad continuous flow of air.

References Cited in the file of this patent UNITED STATES PATENTS 515,374 Sperry Feb. 27, 1894 608,134 Lundell July 26, 1898 1,334,645 Bechoff et al. Mar. 23, 1920 FOREIGN PATENTS 643,772 Germany Apr. 16, 1937 

